What is maximum power and peak torque?

1st December 2020
"There is a piston that gets power from the fuel that is burned to run the motorcycle. The piston is connected to a rod and the rod is connected to a crankshaft."

Being a review team, we often use technical terms like maximum power and peak torque. But what is it really? Why is it one of the most important factors of any automobile to determine the character, feel and ride? We will try explaining it to you in the simplest form.

There is a piston that gets power from the fuel that is burned to run the motorcycle. The piston is connected to a rod and the rod is connected to a crankshaft.

Motor running GIF

Picture a bicycle. The more force you apply in the pedal, the faster the bicycle runs. Similarly, more force from the piston moves the crankshaft faster. Confused?

cycle pedaling

The distance between the pedal to the rotation point is comparable to the distance between the crank and the middle point of the crankshaft, and in the same way, as in the bicycle example, the distance "counts" for 100% when the point of the crank that is connected to the rod has an angle of 90 degrees with the direction of the piston, and for 0% when that point is in the highest or the lowest position. Still, confused?

In simple terms, the more you rev the throttle, the pistons move rapidly which rotates the crankshaft to reach a higher speed.

Bike Engine

The power we feel is the torque. It is expressed in Newton Meter (Nm). The power and revolution per minute provided by that power is the number we state during the engine specification. (Nm@rpm)

The torque provided by the piston varies from rpm to rpm. The torque at any rpm is the average power the piston delivers at the revolution stroke. The amount of power tells how fast the engine can rotate the wheels. Simply putting, torque is the pulling power of a vehicle.

bike engine

Difference between power and torque

Power is the expression of how fast a motorcycle can run when accelerated. It is delivered by the combination of torque and the revolution per minute. When buying an automobile, only looking at the power is not enough. The power collapse after it reaches its limits, and it is the torque that defines the real character and feel of the bike. The advantage of high torque is that you get power from low rpms too.

Or else,  when you ride a motorbike, you will have to change gears a lot, to keep the engine in the high rpm's all the time: in the narrow area where there is power. You will also have to use the clutch when accelerating from a standstill: the engine needs a high rpm to be able to do that.

Power is required in the city streets to cross the traffic in a jiffy and the torque is required when you are cruising down the highway with power in low rpms.


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Compiled by : Debashish S Neupane Debashish S Neupane